The present invention relates to a planetary gear system of an automatic transmission.
A Japanese Utility Model Provisional Publication No. 1-80853 shows an automatic transmission having three planetary gear sets. These three planetary gear sets are almost equal in diametral size, and accordingly the transmission case enclosing these gear sets is not tapered but cylindrical. Therefore, it is difficult to improve the rigidity of the transmission case, and to arrange brakes compactly around the planetary gear sets.